Drying milk.



' C. H. CAMPBELL.

DRYING MILK. APPLICATION FILED 05c. 29. 1913.

Patented Dec. 18,1911.

INVENTOR' WITNESSES:

' STATES PATENT OFFICE.

Y H. CAMPBELL, on NEW YORK, N..Y., assrenoa, Y. mnsnn ASSIGNMENTS, r nonnnn's commnsnn MILK COMPANY, or NEW YOR N. Y., a CORPORATION or NE JERSEY.

Specification of Letters Patent.

DRYING MILK.

Patented Dec.- 18,1917.

' Application filed December 29, 1913. Serial No. 809,297.

To all whom it may concern:

Be it known that I, Cmmns H. Curr- BELL, a citizen of the United States, residing in the borough of Manhattan, city,

county, and .State of New York, have invented certain new and useful Improveing is a specification.

' s ments in Drying Milk, of which th'e follow This invention aims to providea method of making a dry milk which'is highly porous, light and fluffy and-has a high solu-L bilit o The accompanying drawings illustrate more or less diagrammatically apparatus .15 for carryingout'the process.'

Figure 1 showing one style-of apparatus, and i Fig; 2 another style.

In previous patents I have described methods of making'dry milk by eliminating These methods have-produced a product in which the milk. solids are preserved practically unchanged, but the particles are comparatively' dense sothat while of a soluble naturethey have been slow to dissolve in 80 water. The dry milk made b the present invention. is of less density, eing in factlight and porous so that it dissolves more rapidly than that made by previous processes. V a

The desired. result is secured by aerating the thickened milk, by whipping, blowing air through, or other suitable process so as to convert it to a mass whose weight is only one-half or one-third (or even less') that of 40 the saine volume of ordinary milk; and then drying this whipped or foamy mass by anyv one of various methods of exposing large surfaces thereof to hot air. Because of the foamy nature of the mass it solidifies 46 in a porous, friable or crumbly mass which is easily reduced to particles of greater or less size according to the use to which it is to be pm; -Where extreme dryness is important these. solid particles can afterward be further, dried in any one of various ways.

Referring now to the apparatus illustrate d, A is a conoentfator of a type covered in my application No. 7 81,081, filed July 25, 1913, in which the milk may be reduced to 55 a fraction of its original volume by circulat- 'tration inthe first tank A may be carried to such an extent as to reduce the volume to ing... hot water through the jacket B and drums B, and blowing large volumes of air through .the pipes C. When the milk is sufficiently concentrated in this first tank A it may be let out through a valve D into a whipper E of any ordinary type. In the case shown the whipper comprises simply a tank in which is a belt driven shaft F carrying curved wires or rods G which stir the material and aerate it. The construction, as shown in the drawing, is such that the stirring instrumentalities, z. 6., wires or rods, pass through the viscid mass with a smoothly cutting, as distinguished from either an ebulliting or a. kneading, action, whereby is secured indefinitely repeated cutting of the occluded air into smaller and smaller subdivisions with comparatively small levitation or expulsion thereof, or conversion of the mass throughout into mere 76 froth or foam. In this machine the milkis brought to a foamy mass. Therefrom' it passes through a valve H by which the flow can be regulated onto a slowly revolving drum J which is heated internally by hot air or hot water, and upon the outside of which .is a hot air box K having a face fitting fairly close to the drum andprovided with numerous small perforations through which jets .of hot air are blown upon the outer face of the drum. The material' is, as becomes possible owing to its resulting relatively stable,coherent, plastic and-adhesive character, spread on the drum by means of a blade or spreader H iIi"the form of a thin sheet or coating, and after.

one or more revolutions issufficiently dry to be removed. After partial or complete drying of the first coat additional coatsomay be applied and successively dried. After drying the last coata scraper L mounted on arms on a shaft M is pressed against the surface of the drum. As the latter continues to revolve the solidified mass is scraped off and falls into a tray. or other receptacle N from which it may be put in' packages; or it may be further dried and ground and bolted if this be desired.

As an example of my process the concenone-sixth of the original yolume, after which 1 the concentrated milk is run into the whipper E. Or this concentrated milk may be kept for a comparatively long time before an article of commerce, and may be made in the manner described or may be made in various other ways. The milk thus concentrated and run into the whipper is preferably thinned by the addition of a certain amountof water, the added water being, say, 50 per cent. of the volume of the concentrated milk. If the original concentration is greater the amount of water added may be greater. Or where the concentrated milk is run directly from the concentratorinto the Whipper the concentration-may be stopped at an earlier time so as to give the same result, the mass being reduced, say, to onefourth of its. original volume. The thinner the mass introduced into the whipper the more porous the product, and the more quickly the product can be dissolved. Therefore it is desirable to use as thin a milk in the whipper as is practicable. I have found that if it be thinner than about one-fourth of its original volume the whipping does not materially increase its mass, or the air introduced by the whipping is not held in the mass, the milk being too thin to hold theair. Taking milk concentrated to about one-fourth its original volume (either in'the first concentration, or by the greater concentration and subsequent addition of water) it may be whipped and in a comparatively short time increased to two or three times its volume or more. This means, of course, that the volume of air occluded in the milk is equal to once or twice the volume of the milk itself.

The whipped mass shouldbe spread on the drying drum fairly uniformly and evenly. As it dries it shrinks and cracks, due probably to both the shrinkage'and the expansion of air bubbles, and it isf reed very easily from the drum, coming off in a mixture of porous flakes and finer particles due to its crumbly nature.

The apparatus above described are well known apparatus forconcentrating and whipping and drying and may be substituted by other known apparatus for performing.

such operations. A substitute for the drying drum of Fig. 1 is shownin Fig. 2 in which a flexible wire or cloth net 0 runs through the tank P' of whipped milk and runs between spreaders Q and through a pair of hot air boxes R and S, one on each side of the belt. The rate of travel of the belt is such, and the length of the hot air boxes is so proportioned'that a single passage of the belt through the box serves to dry the milk which is carried in a thin sheet in the interstices of the belt. The milk is then readily scraped and brushed off or broken by passing over small rollers U, V, and W, and the residue sucked off by a suction fan T.

An air blast apparatus adapted and regulated to produce the said frothy mass may be used for whipping if preferred. The whipping, besides aerating the product, whitens it by the exposure to air. It will be whipped more or less according to its original condition.

I The material is so spongy when it comes off the drying. roll or drying belt that it is I be separately whipped and added to the whipped, concentrated milk.

The foregoing process assumes that the milk is uncooked, or has not been heated above the coagulating temperature. The process may, however, be used for securing a cooked product. 7 In this case, after concentration the milk is heated by a steam jet directed into the milk and is thus thickened by coagulation, after which it is whipped or aerated in any of the ways above described, and dried in the way above described, or in any other suitable way.

The process is also applicable to the drying of eggs, blood and similar liquids c ontaining solids in solution or in suspension, and produces a similar highly porous, light, fiufly and friable product.

What'I claim is 1. The method of treating milk which comprises first concentrating it; next, converting the concentrate into an aerated, coherent, plastic, adhesive, mass; next, shaping said mass into a sheet of uniform thickness; and, finally, drying said sheet.

2. The method of treating milk which comprises first concentrating it; next, converting the concentrate into an aerated, coherent, plastic, adhesive, mass; next, spreading said mass upon an air-permeable support; and, finally, drylng it.

3. The method of treating milk which comprises first concentrating it; next, con verting the concentrate into an aerated, coherent, plastic, adhesive, mass; next, passing through said mass a pervious belt hav ing interstices; and, finally, drying the porverting the concentrate into an aerated, coherent, plastic, adhesive, mass; next, passing through said mass a pervious belt having interstices; next, imparting to the por tions of said mass adherent to, and carried by, said belt, the form of a sheet of univform thickness; and, finally, drying said next, concentrating the thus skimmed milk;

converting said concentrate into an interlorly aerated coherent, plastic, adhesive,

mass; aerating the cream; adding it to said mass; and drying the resulting mixture.

7 The methodv of treating milk which comprises first concentrating it next, heating itabove the coagulating temperature; next,

converting theso heated'concentrate into an interiorly aerated, coherent, plastic, adhesive, mass; and, finally, drying said mass.

8. The method of treating milk which comprises first concentrating it; next convertingthe concentrate into an aerated, coherent, plastic, adhesive, mass; next spreading said mass upon a flexible wire net, and finally drying it. I

In witness whereof, I have hereunto signed my name in the presence of two sub- 30 scribing witnesses.

CHARLES H. CAMPBELL.

Witnesses? FRED WHITE, Y WILLIAM F. MARTINEZ. 

